Сравните дроби: 1) \frac{9}{10} и \frac{4}{5}; 2) \frac{4}{7} и \frac{2}{3}.

1) \frac{9}{10} и \frac{4}{5} = \frac{8}{10}. \frac{9}{10} > \frac{8}{10}, значит, \frac{9}{10} > \frac{4}{5}. 2) \frac{4}{7} = \frac{12}{21} и \frac{2}{3} = \frac{14}{21}. \frac{12}{21} < \frac{14}{21}, значит, \frac{4}{7} < \frac{2}{3}.